Pipe joint



May 3, 1932 J. c. MITCHELL 1,856,580

PIPE JOINT Filedl March 18, 1926 Patented May 3, i932I UNITED STATES y PATENT o1-Fica JQHNZC. M ITCHELL, OFBLOOMFIELD, 4NEW JERSEY, ASSIGNOR T0 LOCK-J'OINT PIPE COMPANY, F AMPERE, NEW JERSEY, A CORERATION OIEv NEW JERSEY 4PIIEE JOINT 'Application led March 18, 1,926. Serial No. 95,535.

rlhis invention pertains to improvements l in the pipe jointl disclosed in'Patent` No.

. ship. with the pipe ends by and during the forcible insertion .of the spigot end Ninto the -in combination with an annular compressible gasket which Vis forced into'sealing relationbell end. f

In the above disclosed structure the oom,-v pressible gasket was made in the .most convenient manner-by using ordinary commerciall lead pipe, bought on the openmarket,

, drawing resilient fibrous material through the pipe, flattening to desired thickness, cutting to length, and fusing the ends together to form rings. -I l Such a method produced a serviceable and "fairly satisfactory gasket, but experience has taught that for best results, under all conditions of service, the details of the joint should be modified, particularly the distribution of metal in the gasket, and it is toward such improvements that my present invention" is directed. l

Further and other objects and advantages will be hereinafter set forth in the accom panying specification and claims and'sho'wn in the drawings, which byway of illustra- Ation show what is now considered to be the preferred embodiment of the invention.

Fig. l is a sectional view showing the gasket in position in the bell of a metal pipe,

v before the spigot is forced to place.

Fig. 2 is the same asf Fig. 1 after the joint is made.

Fig. 3 shows the joint applied to concrete pipe, after the gasket has been hand caulked.

The spigot portion of the joint comprises acylindricalportion and a tapered end; portion 12. The bell portion of the joint comprises a bottom ring shaped surface 14, a cylindrical portion 16, and a gasket-receiving recessed portion which may be of any desired contour but which is shown as comprising an abutment ring surface 18 joined by a cone shaped surface 20, a cylindrical portion 22, and anannular recess 24 in surface 22.

The gasket 26 is preferably formed by an extrusion process, with substantially the cross section shown'in Fig.v 1. The cross section shows a Vsubstantially rectangular portion and an inclined portion. The inclined portion is of such shape as to fit into the annular conical recess formed in the. pipe bell by surfaces 18 and 20. The inclined portion has approximately the same amount of metal per unit of length as the straight portion, but is f provided with a flattened tubular passage parallel tothe inclined walls, for the accommodation of fibrous material 28. lThe forming of this passage thickens the inclined portion .of the gasket so that it projects, as at 30, into thepath of the incoming spigot end of the next length of pipe.

The gaskets are formed by extruding metal -with the above described cross section, drawing fibrous material through the hollow portion, cutting to'length, and joining the ends of each length, by soldering or fusing, to form a ring of proper length for insertion as indicated vin Fig. 1. As the diameter of the gasket is greater than the diameter of the mouth of the bell, it is necessary to crimp or distort the gasket from its circular shape while `putting it in place.

After the spigot has been forced into the bell, the gasket assumes substantially the shape shown in-Fig. 2. The shape ofthe precompressed ring was such as to permit the reformed material to take the shape illustrated, which is a form found highly eflicient for the desired purpose. In this form the fibrous material is compressed into a comparatively long narrow cross section extending lengthwise of the pipe, and the straight portion 26 lof the gasket extends towards the open end It may sometimes happen that a joint springs a leak-due, for` instance, to displacement of the pipe on account of shifting supports therefor, and it then becomes important to be able to caulk the joint by hand in order to take up the leak. Such a caulking operation is impractical with the type of gasket shown in the patent above referred to, because the exposed edge of the gasketdoes not offer enough metal for the purpose, and because any caulking of the exposed edge might cut through the wall of the metal and allow the escape of fibrous materiahthus reducing the expansive value of the fibrous core and making i necessary the entire rep-acking of the oln l/The present `design of gasket completely overcomes the above mentioned defect by providing the material 26 which may be successfully hand caulked.

The condition of the gasket after caulking is illustrated in Fig.' 3, which shows a cross section of'a joint of a concrete pipe. The pipe comprises the concrete sections 32 and 34,

formed around steel shells 36 and 38 respectively, and in which spigot end 38 and bell end 40 are inserted, the spigot and bell ends being of metal, usually cast iron.

- The gasket has been caulked until the portion which 'originally occupied the dotted space 26 has been compressed into the solid outline, completely filling the circumferen- \tial groove 24 provided for the purpose.

It will be noted that this gasket permits the making of a tight joint by hand caulking, even though the spigot end,`gasket, and bell end are not so proportioned as to make a tight joint in the usual self-caulking manner. `In other words, the gasket may be placed comparatively loosely between bell and spigot, and the joint then made'tight by c'aulking the gasket.

In the design disclosed in the above patent,

a circumferential groove was provided in the pipe bell,I somewhat similar to the .present groove formed by'surfaces 18.and 20, but noattempt was made to fit the gasket into that groove until pressure `was applied, whereupon the metal was expected to flow suiciently to completely lill the space, which it did not always do perfectly, thereby inviting a leak at the point not properly filled. In the present designall possibility of such a defeet is obvia-ted byl so forming the gasket s 'i imbedded therein, the thickness of the ductile material radially adjacent said resilient mateform volume of ductile material per unit of axial length, said material being provided with a circumferential cavity near one edge, saiill cavity being filled with resilient materia In testimony whereofI hereto aihiz my signature.

- JOHN C. MITCHELL.

that it tsthe groove before pressure is apf plied. v

From the above description it will be evii dent that my present invention discloses a design of pipe joint in which the possibility of defect is reduced to a minimum; which may be made tight by self-caulking when the spigot is forced into the bell; which may be made tight entirely by hand-caulking, or 'by a combination of selfcaulking and handcaulking; and which may at any time 'be tightened by hand-caulking.

It is to be understood that the invention is not limited to the construction herein speciiically illustrated but can be embodied in other forms without departure from its spirit.`

.I claim@l 1. A gasket' f or the purpose described, comprising in v`combination, a ring of ductile material, vand a ring of resillent material' 

